The importance of maintaining your airplane

[Big Pistons Forever]

From level turn thread

Further investigation showed that the factory swivel connection at the fuel valve had been replaced by a homemade part sometime in the aircraft's history. The valve had become stiff, as they do with age, and this bogus fitting had bent. The bending, combined with the stiffness, resulted in the valve not shutting off completely. This allowed enough fuel for a run-up and taxiing, but not enough to sustain takeoff power. Had the valve shut off properly, the engine would have started but run out of fuel before I got to the run-up bay, thus alerting even me that something wasn't quite right.

Two previous owners had never used the fuel shut-off, and of course had never had a problem, as the valve was always full on. The current owner was in the habit of shutting off the fuel. He had previously owned a Champ and shut the fuel off after each flight due to a leak through the carburettor. I have never shut off the fuel in my Stinson and never even thought about the valve. However, had I taken the time to use the printed checklist stashed up high on the right side of the cabin, none of this would have happened.

"home made" parts don't have any place in airplanes. If the carb is leaking the solution is not to turn the fuel off it is to fix the carb !

For the first time ever the category "mechanical failure" is now the 2nd highest cause of fatal accidents in Canada. This is a worrying trend and completely within the power of the pilot to influence

[digits_]

For the first time ever the category "mechanical failure" is now the 2nd highest cause of fatal accidents in Canada. This is a worrying trend and completely within the power of the pilot to influence

What used to be the 2nd highest cause? What are the other causes?

Statements like those above -although well intended- always seem a bit empty to me. In the end it is always someone who screws up: pilot, ame, manufacturer,... If you fix one, by comparison another will become more prevalent.

In a world where fatal crashes are becoming exceedingly rare, one incident can influence the statistics enormously.

[photofly]

Weather will be number one; then CFIT.

[PilotDAR]

An important element, and one the pilot can easily accomplish, is to make sure everything you control does what it is supposed to do, the way it's supposed to do it. As a part of this, most flight manuals provide at lease some system descriptions. It is your responsibility to be familiar with operation, and expected effects - so to some extent - defects, when you see them.

When you prepare to fly a plane following maintenance, you check that everything works, that should occur more frequently than just after maintenance. And yes, for the fuel selector, turn it off during a ground run, and wait for the engine to stop. You are confirming that it does and getting a sense of how long the engine continues to run with the fuel turned off.

I do concede that some controls are either wired off for emergency use only, or are trained or urban legend not to be regularly used - that's unfortunate. So, ask the maintenance staff the question - can I operate that? Any cautions? The first time I ever did a manual gear extension in a Cessna 310, was for real, and it was not smooth. I had been trained not to practice with the system. Last summer, for the first time, I was invited to operate a PT-6 with the standby throttle on a Turbo Beaver, as I have been trained that it's a "do not practice with" on the Caravan. So, if there's a control you should not practice with, that's an extra signal to get an understanding of it, 'cause the first time you use it, things will have gone wrong already!

[iflyforpie]

It’s like the parking brake in a car. Either you always use it (typically with a standard) or you never use it (typically with an automatic).

We imported a Cherokee 6 from the southern USA and one of the pilots once we got it online decided he’d try to see if the heat worked... in June in the Okanagan. We’ll you can probably predict what happened and it was not fun flying around that greenhouse of an aircraft in 30C in the condition it was stuck in.

However, there are a lot of things that are just bogus with certified parts. Like how we did a commercial C of A for a Citabria and TC told us we had to take the gel cell out of it an install a lead acid battery. Then we had to install a battery box that could vent all of the hydrogen gas and drain all of the acid that leaked out during aerobatics. Then we had to write in our maintenance schedule to service it every 10 hours. And of course, they never lasted more than a year because trying to get the right ratio of acid to water is nearly impossible (normally you only add water to a lead acid battery, but doing that when it leaks out rather than boils off results in a far too low SG).

I’ll never put vented lead acid battery in an aircraft again if I don’t have to.

[CpnCrunch]

It also shows the importance of using a checklist. Some people don't bother with a checklist, which I guess is fine as long as you can remember every single step. This pilot certainly didn't!

[Big Pistons Forever]

Weather will be number one; then CFIT.

See page four of the Aviation Safety Letter 1/2018

https://www.tc.gc.ca/media/documents/ca ... 18-eng.pdf



The numbers above are from the TC Aviation Safety letter 1 of 2018. I miss remembered the order but I think it is very significant that of the fatal accidents 30 of the 40 in which a cause could be determined were Loss of Control or Low Altitude operations, which suggest issues with pilot proficiency, and mechanical failure which suggest maintenance issues.

[jakeandelwood]

I thought there was something in the CARs about "owner produced parts" but I can't seem to find it. I made a couple of new fiberglass wing root adapters for the rear seat vents on my Cessna but obviously those have no bearing on aircraft safety or reliability.

[PilotDAR]

Certain parts may be "made" in accordance with the proper data. That's the standard which allows you to replace a skin from stock aluminum sheet, rather buying a skin from the manufacturer. In the case of Cessna, they generally tell you what material to use, so that gets you pretty well down the road of having the data. Other parts would be tough to justify as being made, and some simply impossible to "make".

But, the catch is that many of the parts which are easy to make (like skins) may become a "structural repair" for which the signatory might have to be an AMO with a structures rating. In any case, an AME/AMO must sign out the made part in accordance with the standard, and correct data. So as long as your AME is okay signing out your fiberglass adapters, that sounds okay... A fuel selector part would unlikely be a candidate for a made part.

Certainly, good maintenance is sometimes best accomplished by making a replacement part, rather than trying to patch a worn out one.